DESCRIPTION (Applicant's Abstract):The overall objectives of the Pathology Core are: first, to use qualitative and quantitative morphological methods to provide as extensive as possible a pathological evaluation of each clinical and experimental specimen submitted for study; second, to undertake the collaborative development and assessment of new methods and techniques for the morphological evaluation of the mechanisms of arterial thrombosis; and third, to apply newly developed techniques to the pathological study of vascular thrombosis. This core has an excellent history of collaboration with the investigators of the current Thrombosis SCOR (see publications list) and we will continue this interaction in this new proposal(note numerous photomicrographs in the proposal). The specific aims of the Pathology Core are: 1. Provide a resource for procuring, characterizing and managing of both clinical and experimental tissue samples for the projects of this SCOR. 2. Provide a full range of morphological techniques for identification of vascular wall and thrombus related cellular elements and proteins. 3. Provide morphometric and image processing techniques for the quantitative evaluation of clinical and experimental specimens. 4. To examine human myocardial tissues for changes in tissue factor antigen content in disease states, to examine human lung tissue for evidence of tissue factor expression and with smoking and other diseases, and to examine tissue factor expression in tumors associated with intravascular thrombotic events.